Base plates are used in ostomy appliances to attach ostomy bags to the skin of a user having a stoma, the user also being referred to as an ostomate or ostomist.
The base plate is typically formed by a backing layer, e.g. a polyurethane film, on which a skin friendly adhesive is disposed. A through-going passage is arranged in the base plate to receive a stoma so that the base plate may be adhered to the skin surrounding the stoma.
In order to collect output from the stoma, the opening of an ostomy bag is arranged around the through-going passage. The ostomy bag may, for example, be arranged by welding the bag to the backing layer of the base plate. In the art, this is referred to as a one-piece ostomy appliance. Alternatively, a coupling arrangement, either adhesive or mechanical, may be arranged so that ostomy bags may be arranged detachably on the base plate. This allows the bag to be changed when full without detaching the base plate from the skin. In the art, this is referred to as a two-piece ostomy appliance.
A number of ostomates develop sunken or retracted stomas. This is a phenomenon where the stoma sinks into the abdomen creating a recess or cavity in the stomach where the stoma is placed. Applying a standard planar base plate around such a retracted stoma would, for one thing, leave the peristomal skin area immediately around the stoma uncovered and thereby exposed to the output from the stoma. Moreover, in some cases, the stoma is retracted so much that it is not even possible for it to extend or protrude through the through-going passage in the base plate. This means that the risk of leakage is increased. By leakage is meant that the stomal output containing aggressive, enzymatic fluids, enters underneath the adhesive of the base plate and leading to adhesion failure. In order to address the issue of retracted stomas, and the consequently encountered frequent leakage problems, convex base plates have been developed.
Basically, these have a convex surface contour where an outer planar area is adhered to an outer skin area which surrounds the stoma, but where the skin is not pulled inwards towards the stoma. An intermediate area of the convex surface, having a slanting surface along the axis of the through-going passage, adheres to the skin area between the outer skin area and the inner skin area described hereafter. Finally, an inner planar area of the convex surface is adhered to an inner skin area immediately surrounding the stoma.
Such products have been available on the markets for many years. Their primary purposes and advantages are that they are able to prevent the peristomal skin of the ostomist's body from collapsing on to the stoma and practically closing off the stoma, e.g. due to excess skin folds caused by overweight or obesity. Such collapse potentially causes a dislodgement of the product from the body. Another purpose of the convex products is to increase the ability of the stoma to protrude adequately past the interface between the base plate and the body surface by maintaining a necessary pressure in the peristomal skin area, thus making sure that the stomal output deposits directly into the collecting bag.
Generally, however, these products are relatively stiff and inflexible and will not follow the ostomist's body movements caused by physical activity very well. More severely, experience has shown that the use of these products may in some cases result in peristomal skin damage such as pressure wound ulceration and bruises.
In more recent years, an increased variety of convex base plate products have been made available to ostomists. Particularly, if the recess or cavity in the body may be relatively shallow, i.e. when the stoma is only retracted to a lesser degree, a less bulky and less stiff convex base plate may be appropriate. Furthermore, there has been a desire to alleviate at least some of the user-experienced discomfort caused by the stiffness and inflexibility of the known stiff convex base plates. To overcome these and other needs, what is commonly accepted as “soft convex base plates” have been developed. These have a higher degree of flexibility than the stiff convex base plates and thus improve user comfort. These products may or may not comprise an injection moulded convex element. However, the increased flexibility and comfort of the “soft convex base plates” products have compromised their ability to maintain the necessary pressure on the peristomal skin area to keep the stoma adequately protruding.
Thus, there is an unmet need to improve convex base plates so as to provide products that can maintain a relatively constant and adequate pressure in the peristomal skin area without simultaneously compromising the improved flexibility experiences with the soft convex base plates.